Cell processing using magnetic particles

Abstract

The present invention relates to compositions comprising magnetic particles, the methods of using these compositions in processing animal sperm, the resulting sperm and embryo products, and the methods of use of these compositions to increase the efficiency, efficacy and/or speed of cell processing and artificial insemination techniques.

The invention claimed is: 
     
       1. A method of processing sperm cells comprising the steps of:
 a) forming a stream comprising the sperm cells; 
 b) determining whether a property of interest is present or absent in the sperm cells in the stream; 
 c) ablating or photodamaging a subpopulation of the sperm cells based on the presence or absence of the property of interest in the sperm cells; 
 d) collecting the sperm cells; 
 e) adding magnetic particles to the collected sperm cells to form a mixture, the magnetic particles having a diameter of 30 to 1000 nm and comprising a chargeable silicon-containing compound, the magnetic particles binding to the ablated or photodamaged subpopulation of sperm cells solely through an electrical charge interaction; 
 f) applying a magnetic field to the magnetic particle-bound sperm cells; and 
 g) removing the magnetic particle-bound subpopulation from the mixture. 
 
     
     
       2. The method of  claim 1 , the magnetic particles comprising an outer layer comprising a polysaccharide, an alkylsilane, a polylactic acid, a polycaprolactone, polyhydroxybutyrate-valerate or a polyolefin. 
     
     
       3. The method of  claim 2 , the outer layer further comprising a chargeable, or charged, moiety. 
     
     
       4. The method of  claim 3 , the chargeable, or charged, moiety comprising a metal, an oxide, a carboxylate, an amine, an amide, a carbamide, a sulfate, a sulfonate, a sulfite, a phosphonate, a phosphate, a halide or a hydroxide. 
     
     
       5. The method of  claim 1 , wherein the mixture has a pH of 6.5 to 8.0. 
     
     
       6. The method of  claim 1 , wherein the mixture comprises a buffer. 
     
     
       7. The method of  claim 1 , wherein the mixture comprises sperm cells at a concentration of 120×10 6  cells/ml to 500×10 6  cells/ml. 
     
     
       8. The method of  claim 1 , wherein the magnetic particles are non-toxic to the sperm cells.